In the course of daily affairs. we are frequently asked or required to recollect the same events from memory. This repeated recollection may occur in educational contexts, as when people are tested on material during the course of a semester and later receive a cumulative final exam. Similarly, eyewitnesses to crimes may be queried repeatedly about what they observed by police, by friends, by lawyers, and then eventualIy in court. More commonly, we all repeatedly retell stories of favorite or notable events in our lives. Despite the ubiquity of such experiences, the ftralegy of repeatedly testing memory has not been the dominant method of studying how memories change over time. Rather, researchers have generally employed between-subjects comparisons, in which . Address correspondeliLc: L, ,*iilhor\ at the Department of Psychology. Rice U n i v usity, Houston, TX 77,-7 i i . l X i i 3 independent groups learn some material irnd then are tested at various times after thc original learning to measure the course of forgetting. This design has the advantage of delayed tests being uncontaminated by recollections on previous tests. as would occur if a within-subjects design were used. However. the "contaminating" influences of previous tests can be of central interest in their own right, with the eyewitness testimony situation representing a prime example (Loftus, 1979). Therefore, the repeated testing of memory for the same events (without intervening study opportunities) also represents a valid, if less used, approach to changes in retention over time.Several experimental paradigms and research traditions have been used to examine effects of repeated testing on memory. For present purposes, we confine interest to those cases in which the tests were given without overt cues (free recall). The most famous example of this technique is that of Bartlett (1932), who gave college students the Indian folktale "The War of the Ghosts" and then tested them repeatedly. He presented no aggregate data to support his conclusions, but rather provided sample recall protocols from his subjects. He reported that their performance became increasingly poor over time; they forgot the story but reconstructed plausible accounts that were skewed to the more typical schema of a fairy tale, a style that was presumably more familiar to his students. Despite the fact that Bartlett (1932, pp. 3-4) criticized the pioneering work of Ebbinghaus (1885/1964), his conclusions about the course of forgetting were broadly consistent with Ebbinghaus's prior work. Of course, his theoretical emphasis was markedly different.Curiously. a second tradition of repeated testing research, begun by Ballard ( I9 13). leads to the opposite conclusion from Bartlett's belter publicized work. Ballard gave schoolchildren poetry and Ic.,led their memories both soon after learning and then again at various periods up to I week later. He reported that children frequently recalled lines of poetry on later tests that were not recalled on earlier ones, a phenomenon he termed r...